44 DISEASES OF TREES 



on or in variously shaped sporophores. The shape of the 

 sporophore is much more characteristic of the species than the 

 mycelium, and as the sporophore (which often grows to a large 

 size) is almost always outside the nutrient substratum, whereas 

 the mycelium is hidden in it, the uninitiated often regard the 

 sporophore as the whole fungus, and pay little or no attention 

 to the mycelium. 



When the sporophore consists only of single filaments 

 springing from the mycelium, it is called a simple or filamentous 

 sporophore, whereas the compound fungus-body goes by the 

 name of a compound sporophore. On account of the great 

 variety in shape and structure exhibited by the sporophore, it 

 would be going beyond our limits were we to consider it more 

 closely at this time.* Cells which are called spores are separated 

 off in some w r ay or other in or on the sporophore, and these by 

 germinating give rise to new individuals. The cells, from which 

 spores directly originate, are known as sporogenous cells. The 

 spores are produced either internally, as in the case of the 

 sporangia of the Phycomycetes, and the pouches or asci of the 

 Ascomycetes, or by apical abscission, in which case the mother- 

 cell is often called a basidium. 



In the case of some groups of fungi, sexual processes have 

 been proved to exist."f- The course of development, as in other 

 plants, has been divided into two sections (generations), of which 

 the one called the a-sexual generation begins with the germi- 

 nation of a sexually fertilized cell, and leads to the production 

 of spores (oospores ; zygospores). The germination of these 

 spores gives rise to the second generation, which, in form and 

 development, is essentially different from the a-sexual plant. It 

 ends with the formation of the male and female sexual 

 apparatus and sexual cells, and on this account is called the 

 sexual generation. Spores which do not mark the close of the 

 a-sexual generation, but which, like buds, brood-cells, and other 



*[The student may be referred to the works of De Bary, Zopf, and Von 

 Tavel for details. ED.] 



f [Such a book as this is, of course, not concerned with the morphological 

 details of this difficult and involved matter, and the student is referred to the 

 works of Tulasne, De Bary, Zopf, and Brefeld for particulars of the subject. 

 The outcome of recent researches is to show that sexuality has disappeared 

 in the case of most fungi. ED.] 



